(1) Field of the Invention
The present invention relates to solidification agents for solidifying such radioactive waste as concentrated liquid waste and spent ion exchange resin (called spent resin hereinafter) etc. and a method for processing the radioactive waste, and, especially, to preferable solidification agents for improving retainability for radioactive nuclides, particularly C-14, in the radioactive waste, and a method for processing the radioactive waste.
(2) Description of the Prior Art
Low level radioactive wastes which are generated at radioactive material handling facilities such as nuclear power plants are safely solidified with ordinary portland cement or plastics as disclosed in JP-A-63-289500 (1988).
As for cementitious solidification agents, ordinary portland cement shares more than 30%, and the residual is shared with cements of which the main components are slag, and fly-ash, or cement-glass of which the main component is sodium silicates. By solidification of the radioactive waste with the above described solidification agents, such radioactive nuclides as Co-60, Sr-90, Cs-137, and C-14 in the waste can be retained in the solidified bodies in a sufficiently stable condition.
Additionally, for further improving retainability of a solidified body for the radioactive nuclides, addition of such an adsorbent for radioactive nuclides as zeolite etc. into a solidification agent such as cement is performed as disclosed in JP-A-3-105298 (1991). As the adsorbent has a property to adsorb cations, the retainability of the solidified body for Co-60, Sr-90, and Cs-137 etc. is remarkably improved. However, as C-14 is not a cation, the retainability of the solidified body for C-14 is not improved by the previously described prior art.
The amount of C-14 contained in so-called low level radioactive waste is very small, and accordingly, the low level radioactive waste can be solidified in a sufficiently stable condition even by the prior art. But, in consideration of a long half life of C-14 as about 5700 years, it is preferable to improve further the retainability of the solidified body for C-14.